An example of the lore universe constantly being downscaled is the T'au even being worth mentioning altogether. They have something like 100 developed worlds, the IOM has countless worlds in the truest sense of the word countless.
But they have totally awesome tech!
... That while it may be slightly better than humie variants, if the Adeptus Mechanicus took them seriously, the T'au would be annihilated instantly. Only their plot-armor (everyone is always too busy to pay attention to them) and annoying weaponry saves them.
One thing I found common so far in the pnp games and some of the computer games is that Tau adversaries are stronger than they should: If you let them get into firing range, they will take down even space marines with their rapid fire ion guns. Period.
It's both amusing and annoying that a squad of blue guys with rapid fire energy guns are equally as dangerous or even more than say a bunch of demonic space marines with centuries of battle experience.